To provide quality Internet service to unconnected residences around the globe, it is estimated that by 2020 aggregated user data-rates exceeding 100 Tbps will be required for the portion of the population that would be online simultaneously. The infrastructure required to make such a capacity practical necessitates major advancements in terrestrial, airborne, and space-borne telecommunications technologies.
It is estimated that at several Tbps telecom capacity per spacecraft, Internet delivery via satellites may become cost-competitive with the lowest-cost wired or wireless connectivity technologies. To realize this technological advance in telecom, substantial improvements in the capacity of today's satellite communications networks, whether in geostationary orbit (GEO) or medium-earth-orbit (MEO), low-earth-orbit (LEO) may be required.
Optical frequencies currently have a huge and unregulated spectrum. Current technologies for free-space optical/laser communications (lasercom) may allow multi-Tbps uplink capacity from a ground station to a MEO or GEO satellite along with Tbps-scale downlink capacity via a few beams. Currently, the total single spatial- and longitudinal-mode uplink laser power required to achieve 10 Tbps gateway link capacity per satellite is a limiting factor. Also, due to atmospheric effects, lasercom uplink and downlink availability per station may be limited (e.g., on the order of 50 to 60% for above average ground sites).